[tialaramex]

Also, in generic code write try_into() and don't sweat it, for the cases which can't actually fail in the monomorphised results the error type is Infallible, that's an Empty Type (an enum with no variants, as distinct from a Zero Size Type which is a struct with no members) and so no error handling code is emitted.

The compiler can't even imagine what the code should look like, after all this type can't exist, does it fit in a register? How do we perform operations on it? If we try to actually realise an empty type by e.g. dereferencing a pointer to it that somebody gave us from a C API the Rust compiler will reject that as nonsense.